Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > Section 2- Cell structure > Flashcards

Section 2- Cell structure Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is resolution?

A

The minimum distance apart 2 objects can be in order for the to appear as separate items.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is magnification?

A

How many times bigger the image is when compared to the object.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How do you convert from millimetres to micrometres?

A

Multiply by 1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What of these organelles does a virus have?

  • Cell-surface membrane
  • Nucleus
  • Cytoplasm
  • Capsid
A

Only capsid

no cell-surface membrane, nucleus, cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why can mitochondria look different to one another?

A

Very in shape

Cut in different planes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are 3 reasons why mitosis is important to organisms?

A

Asexual reproduction
Growth in organisms
Repair in organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are 3 ways DNA in chloroplast is different to DNA in nucleus?

A

Fewer genes

Shorter in length

No introns

Circular not linear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why are organelle structures not visible in optical microscopes?

A

Resolution is not high enough

Light microscope have longer wavelength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What organelle is found in both chloroplast and prokaryotic cell?

A

Ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What type of cell wall is found in plants, algae, fungi and prokaryotes?
(cellulose, murein, chitin)

A

Plants: cellulose

Algae: cellulose

Fungi: chitin

Prokaryotes: murein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the structure of a prokaryote?

A

Cell wall

Capsule: protects bacteria form other cells

Cell-surface membrane

Circular DNA

Plasmid: has genes that may aid survival of bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the difference between prokaryotic and eukaryotic cells?

A 
Eukaryotic cells:
Distinct nucleus with envelope
DNA associated with proteins
No plasmids, DNA is linear
Membrane bound organelles
Ribosomes are larger
Prokaryotic:
No nucleus
Some DNA in plasmids
No membrane-bound organelles
Ribosomes are smaller
Cell wall made of murein
Have capsule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What 2 types of molecules are ribosomes made from?

A

Ribosomal RNA

Protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the molecule found in the cell walls of bacterial cells?

A

Murein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why can light microscopes only distinguish between 2 objects if they are 0.2um apart?

A

Due to the relatively long wavelength of light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the evaluative points for a light microscope?

A

Low resolution

  • Due to long wavelength of light
  • Limits magnification

Able to view living specimen

Able to see colour (with stain)

Simple preparation

Artefacts are rare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the evaluative points of an electron microscope?

A

Uses beam of electrons to produce an image

High resolution
-Short wavelength of electrons

Sample must be dead
-Chamber is a vacuum

Image produced is black and white

Preparation is complicated

Artefacts are common

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 2 types of electron microscope?

A

Transmission electron microscope

Scanning electron microscope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a transmission electron microscope?

A

Passes beam of electrons through a very thin specimen

Parts of the specimen allow electrons to pass through and so appear bright

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the limitations of a transmission electron microscope?

A

Difficult preparation limits resolution

System is a vacuum = dead specimen

Image is 2D and black and white

May contain artefacts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a scanning electron microscope?

A

Produced a 3D image of the surface of the object

Resolution isn’t as high

3D image can be built by computer analysis of the pattern and secondary electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 2 processes of cell fractionation?

A

Homogenisation

Ultracentrifugation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What 3 kind of solutions does a tissue need to be placed in before cell fractionation?

A

Cold
Isotonic
Buffer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does a tissue need to be placed in a cold solution before cell fractionation?

A

Reduces activity of enzymes which may break down organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Why does a tissue need to be placed in a isotonic solution before cell fractionation?

A

Prevent shrining and bursting due to osmosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does a tissue need to be placed in a buffer solution before cell fractionation?

A

To maintain a constant pH, avoiding damage to organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why is a tissue firstly placed in a homogeniser and filtered before going in a centrifuge?

A

Releases organelles from the cells

Filtered to remove any whole cells and large debris (cell wall)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the process of cell fractionation?

A
  1. Tissue placed in cold, isotonic, buffer solution.
  2. Homogenisation
  3. Filter homogenate
  4. Centrifuge homogenate and collect sediment
  5. Spin at faster speeds and collect sediment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the order of organelles in the sediment of an animal cell when centrifuged?

A

Nuclei
Mitochondria
Lysosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the structure and function of the mitochondria?

A

Double membrane: controls entry and exit of material

Cristae (extensions of inner membrane): provide large surface area for enzyme attachment

Matrix: contains proteins, lipids, ribosomes, DNA that allow mitochondria to control production of proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the structure and function of the chloroplast?

A

Chloroplast envelope: controls entry and exit of substances

Grana: stacks of thylakoids which contain the chlorophyll
Granal membranes provide large surface area

Stroma: contain starch grains

Grana & stroma: both for photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the structure and function of the chloroplast?

A

Chloroplast envelope: controls entry and exit of substances

Grana: stacks of thylakoids which contain the chlorophyll

Stroma: contain starch grains

Grana & stroma: both for photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the structure and function of the smooth endoplasmic reticulum?

A

Synthesises and processes lipids
Secretes steroids

System of hollow tubes: allows transport of substances within cells

Site of carbohydrate and lipid metabolism

34
Q

What is the structure and function of the rough endoplasmic reticulum?

A

Covered in ribosomes: synthesise proteins which are transported through cell cavities

Hollow tubes: allow transport of substances within the cell

Folds and processes proteins that have been made at the ribosomes.

Provides large surface area for synthesis of proteins and glycoproteins

35
Q

What is the structure and function of the golgi apparatus?

A

Processes and packages new lipids and proteins

Makes lysosomes

Flattened membrane cavities: allows internal transport

Vesicles: contain material to be secreted and protect molecules

Connected to RER: proteins are modified before secretion

36
Q

What is the structure and function of the lysosomes?

A

Vesicles which contain hydrolytic enzyme (lysozyme): break down old organelles

Used to digest invading cells or break down worn out component of the cell

37
Q

What is the structure and function of the ribosome?

A

80s- eukaryotic cells
70s- prokaryotic cells, mitochondria, chloroplast

2 subunits both made of protein and rRNA

Provide binding site for mRNA which allow translocation of DNA code

38
Q

What is the structure and function of the ribosome?

A

80s- eukaryotic cells
70s- prokaryotic cells, mitochondria, chloroplast

2 subunits both made of protein and rRNA

Provide binding site for mRNA which allow translocation of DNA code

39
Q

What is the structure and function of the cell wall?

A

Consists of microfibrils of cellulose embedded in a matrix

Provide strength and rigidity

40
Q

What is the structure and function of the vaculole?

A

Single membrane = tonoplast

Fluid filled sac of cell-sap (sugar & salts)

Helps to maintain pressure inside - stop plant wilting

41
Q

Why is the electron microscope able to resolve objects better than the light microscope?

A

The electron microscope uses a beam of electrons that has a much smaller wavelength than light

42
Q

Why do specimens have to be kept in a near-vacuum in order to be viewed effectively using an electron microscope?

A

Electrons are absorbed by molecules in the air which would prevent the electrons reaching the specimen

43
Q

Why can the theoretical resolving power of an electron microscope not always be achieved?

A

Preparation of specimens may not be good enough

Higher energy electron beam is required and this may destroy the specimen

44
Q

Why can the theoretical resolving power of an electron microscope not always be achieved?

A

Preparation of specimens may not be good enough

Higher energy electron beam is required and this may destroy the specimen

45
Q

What is cell differentiation?

A

When a cell develops specific structures and becomes specialised to carry out a particular function

46
Q

What are some common cell adaptations?

A

Folded membrane / microvilli = increase surface area

Increases mitochondria = large amounts of ATP for active transport

Walls one cell thick to reduce diffusion distance

47
Q

What is the role of plasmids in prokaryotes?

A

Small ring of DNA that carries non-essential genes

48
Q

What is the role of the flagella in prokaryotes?

A

Rotating tail propels organism

49
Q

What is the role of the capsule in prokaryotes?

A

Protects bacterium from other cells and help groups of bacteria to stick together for further protection

50
Q

What is the role of the circular DNA in prokaryotes?

A

Contains genetic material

51
Q

What is the basic structure of a virus?

A

Capsid: protects genetic information

Envelope

Attachment proteins

Genetic information

52
Q

What are the 5 stages of a viruses life cycle?

A 
Attachment
Entry
Replication
Assembly 
Release
53
Q

What are the 3 phases of the cell cyle?

A

Interphase: cell growth and DNA replication
G1= cell growth
S phase= DNA synthesises
G2= proteins synthesised

Nuclear division: mitosis/ meiosis

Cytokinesis: division of cytoplasm

54
Q

What is mitosis for?

A

Growth
Repair
Replacement
Asexual reproduction

55
Q

What is an advantage and disadvantage of mitosis?

A

Genetic make-up of parent has enabled survival and reproduction

Genetic variation is limited

56
Q

What are the 4 phases of mitosis?

A

Prophase
Metaphase
Anaphase
Telophase

57
Q

What happens during prophase of mitosis?

A

Chromosomes condense getting shorter and fatter

Nuclear envelope breaks down, chromosomes lie free

Centrioles start moving opposite ends, forming spindle

58
Q

What happens during metaphase of mitosis?

A

Chromosomes line up along equator

Chromosomes become attached to spindle by centromere

59
Q

What happens during anaphase of mitosis?

A

Centromere divides, separating into chromatids

Spindles contract, pulling chromatids to each pole

60
Q

What happens during telophase of mitosis?

A

Chromatids reach opposite poles on the spindle

Chromatids uncoil, becoming long & thin

Nuclear envelope forms

61
Q

How does cell division in prokaryotes occur?

A

Binary fission

  1. Circular DNA molecule replicated, both copies attach to cell membrane
  2. Cell membrane begins to grow between 2 DNA molecules, begins to pinch inwards
  3. New cell wall forms between 2 molecules of DNA, divides original cell into 2 identical daughter cells
62
Q

What are malignant tumours?

A

Grow rapidly
Less compact
Invade surrounding tissues
More likely to be life-threatening

63
Q

What is cancer caused by?

A

Mutation in gene causes uncontrolled mitosis

Mutations can form clones of themselves, forming tumours

64
Q

How do drugs normally treat cancer?

A

Prevent DNA replicating

Inhibit metaphase by interfering with spindle formation

65
Q

Why do ciliated cells contain relatively large numbers of mitochondria?

A

ATP produced is needed for the movement/ wafting of cilia.

66
Q

Compare and contrast the DNA in eukaryotic cells with the DNA in prokaryotic cells.

A

Nucleotide structure is identical
Nucleotides joined by phosphodiester bond

Eukaryotic DNA is longer, contains introns

Eukaryotic DNA is linear, prokaryotic is circular

Eukaryotic DNA is associated with histones, prokaryotic is not.

67
Q

What would be a method of testing for starch?

A

Thin slice sample

Stain with iodine

68
Q

Why would a student use a homogeniser?

A

To break open cells

69
Q

Why would a solution be buffered?

A

No change in pH

To prevent denaturation of proteins

70
Q

Why would students use a stain that turns DNA blue when observing mitosis?

A

Make chromosome visible

Chromosome contains DNA

71
Q

What would be a method of displaying results in a pie chart?

A

Draw circle

(Number of section/ Total number) X 360

Use protractor

72
Q

What is the stage of the cell cycle during which chromosomes replicate?

A

S phase in Interphase

73
Q

What is a process that occurs during G1 and G2 of the cell cycle?

A

Growth of cell

74
Q

How common is a flagellum in eukaryotic and prokaryotic cells?

A

Sometimes present in both

75
Q

How could you improve a biological drawing?

A 
No shading
No overlapping lines
Scale
Title
Labels of key features
76
Q

When a fish is removed from water, their lamellae stick together.
How can this be damaging to fish?

A

Lamellae stick together, surface area is reduced so not enough oxygen is absorbed

77
Q

A different set of results were obtained when count was repeated in mitotic index with a different garlic root tip. Give two reasons for the difference in results.

A

Genetic difference, time, chance, age of root tip

78
Q

What are 2 reasons why it is important to the count number of organelles in several parts of a tissue?

A

To obtain a reliable mean

Distribution may not be uniform

79
Q

What happens within a vacuole after it fuses with the lysosome?

A

Enzymes used in hydrolysis

Digestion of bond

80
Q

Why would an image of low magnification be of little use when studying cells?

A

Low resolution as wavelength of light is too long

81
Q

Why do ciliated cells contain large numbers of mitochondria?

A

ATP is needed for movement of cilia

Biology (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions